Filter apparatus with pulse cleaning and methods for pulse cleaning filters

ABSTRACT

A method of pulse cleaning filter media in panel, cylindrical, conical, or V-pack style filter in an opening of a tubesheet is provided. The method includes directing a fluid pulse at the filter media at an angle that is: (i) not normal to a plane of the opening of the tubesheet; and (ii) not in line with the general direction of the filtration flow through the filter media. An air cleaner is provided including a housing including a dirty air inlet, a clean air outlet, and an interior. A tubesheet is in the housing interior having a plurality of openings. In the plurality of openings of the tubesheet are mounted filters with filter media. There is a plurality of blow pipes, with each blow pipe being pointed to direct at a fluid pulse a respective one of the filters at an angle that is: (i) not normal to a plane of the opening in the tubesheet; and (ii) not in line with the general direction of filtration flow through the respective filter media.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from provisional application Ser. No.60/867,843, filed Nov. 30, 2006, and which is incorporated herein byreference.

TECHNICAL FIELD

This disclosure relates to methods for pulse cleaning filter elementsutilizing pressurized gas generators. This disclosure also relates toapparatus including air cleaners, dust filters, and pulse cleaningtechnology.

BACKGROUND

Air cleaners or dust collector devices sometimes use exhaust gas from avalve and pressure tank (reservoir) to back flush filters. Examples ofsuch air filters assemblies are disclosed in, for example, U.S. Pat.Nos. 6,090,173; 4,218,227; 4,395,269; 5,980,598; 6,322,618; DE 3905113;and Patent Publication U.S. 2006/0112667A1, each of these patentdocuments being incorporated by reference herein.

Effective cleaning of these filters requires that the exhaust jet fillthe opening of the filter to be cleaned. In many implementations, theopening of the filter corresponds to the opening in the tubesheet, inwhich the filter is mounted. Improvements in pulse cleaning filters aredesirable.

SUMMARY

A method of pulse cleaning filter media in a panel, cylindrical, conicalor V-pack style filter, mounted in an opening of a tubesheet isprovided. The method includes directing a fluid pulse at the filtermedia at an angle that is: (i) not normal to a plane of the opening ofthe tubesheet; and (ii) not in-line with the general direction of thefiltration flow through the media.

As used throughout this specification, “normal” means 90°±5°, and“in-line”, it is meant 0°±5°.

An air cleaner is provided including a housing including a dirty airinlet, a clean air outlet, and an interior. A tubesheet is in thehousing interior having a plurality of openings. In the plurality ofopenings of the tubesheet are mounted filter media in the form ofpanel-style, cylindrical, conical, or v-pack filters. There is aplurality of blow pipes, with each blow pipe being pointed to direct afluid pulse at a respective one of the openings in the tubesheet holdingone of the filters. The pulse is directed at an angle that is: (i) notnormal to a plane of the opening in the tubesheet; and (ii) not in linewith the general direction of filtration flow through the respectivepanel-style filter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view, partially broken away, of oneembodiment of an air filter system utilizing principles of thisdisclosure;

FIG. 2 is a schematic side elevational view illustrating principles ofthis disclosure;

FIG. 3 is a schematic diagram illustrating principles of thisdisclosure;

FIG. 4 is a schematic diagram illustrating principles of thisdisclosure;

FIG. 5 is a schematic diagram illustrating principles of this disclosureon either a V-pack filter or a conical filter;

FIG. 6 is a schematic diagram illustrating principles of this disclosureon cylindrical filter;

FIG. 7A is a schematic diagram illustrating principles of thisdisclosure on multiple cylindrical filters;

FIG. 7B is a schematic diagram illustrating principles of thisdisclosure on combination conical/cylindrical filters; and

FIG. 8 is a schematic diagram illustrating principles of this disclosureincluding having more than one blowpipe pulse cleaning a filterarrangement.

DETAILED DESCRIPTION

A dust filter or air cleaner system is depicted generally at 10 inFIG. 1. The system depicted includes a housing 12 having a side wallpanel 17 broken away to illustrate the arrangement of various portionsof the assembly. An upper wall panel 16 has an inner wall surface 19. Inthis embodiment, an air inlet 20 is positioned in the upper wall panel16 so that the particulate-laden air or other fluid is introduced intoan unfiltered (dirty) fluid chamber 22. The unfiltered chamber 22 isdefined by an access door 13, the upper wall panel 16, opposing sidewall panels 17, a tubesheet 28, and a bottom surface 23 partiallydefining a collection area or hopper 25. The bottom base panel or frame26 is secured to the side wall panels 17 in a suitable manner.

As mentioned above, the tubesheet 28 is mounted in the interior of thehousing 12. The tubesheet 28 includes a plurality of openings 30. Withineach opening 30 is mounted one or more filter elements, which in theillustrated embodiment, is a panel-style filter element 32. By the term“panel-style filter element” it is meant an element with filter media inwhich, in general, fluid to the filtered flows through the filterelement in a straight-flow thorough manner. For example, a panel-stylefilter element can be pleated media, depth media, fluted media, Z-media,or mini V-packs. By “Z-media”, it is meant media having first and secondopposite flow faces with a plurality of flutes, each of the fluteshaving an upstream portion adjacent to the first flow face and adownstream portion adjacent to second flow face, selected ones at theflutes being open at the upstream portion and closed at the downstreamportion, while selected ones of the flutes are closed at the upstreamportion and open at the downstream portion. The flutes can be straight,tapered, or darted. Examples of filter elements with Z-media are foundin, for example, U.S. Pat. No. 5,820,646; Patent Publication2003/0121845; and U.S. Pat. No. 6,350,291, each of these patentdocuments being incorporated by reference herein.

In operation, fluid, such as air, to be filtered flows into the system10 through the inlet 20. From there, it flows through the filterelements 32. The filter elements 32 remove particulate material from thefluid. The filtered fluid then flows into the clean air or filtered flowchamber 15. From there, the clean air flows through an outlet 34.Periodically, the filter elements 32 will be cleaned by pulsing a fluidjet, such as a jet of air, from a downstream side 36 of the filterelement 32 to an upstream side 38 of the filter element 32.Specifically, a jet of pressurized gas will be directed throughindividual blow pipes 40, a respective blow pipe being oriented for eachof the respective filter elements 32. This will direct the jet througheach filter element 32, from the downstream side 36 to the upstream side38. This helps to knock debris and particulate from the upstream side 38of the filter element 32, directing it off the filter element 32 andinto a hopper.

A schematic illustration of the portion of the system 10 is illustratedin FIG. 2. In FIG. 2, the blow pipe 40 can be seen oriented with respectone the filter elements 32 in the opening 30 in the tubesheet 28. InFIG. 2, it can be seen how the blow pipe 40 is oriented relative to thefilter element 32 in a plane 60 (FIG. 3) that contains the respectiveopening 30 in the tubesheet 28 for the respective filter element 32,such that a pulse that comes from the blow pipe 40 is at an angle thatis not normal to a plane of the opening 30 and is not in line with ageneral direction of filtration flow through the filter element 32. Bythe term “not normal”, it is meant non-orthogonal, such as at an acuteor obtuse angle relative to the plane 60 that contains the opening 30for the respective filter element 32. By “not in line with a generaldirection of filtration flow”, it is meant, for a straight-through flowfilter, the pulse flow is in a direction that is not parallel to theflow of direction through the filter element 32. By directing the fluidpulse at the filter element 32 at such an angle 64, the exhaust jet,which expands at a predictable angle, creates a diameter D2 (FIG. 3)larger in one direction that a diameter D1 that is typically used in theprior art.

While the illustrated embodiment shows only a single blowpipe 40corresponding to a single filter element 32, it should be understoodthat in many implementations, there are more than one blowpipe 40 foreach element 32.

In a preferred embodiment, at least a portion of the pulse is trapped byusing an accumulator arrangement 42. The accumulator arrangement 42captures the flow of the pulse from the blow pipe 40. In one embodiment,the accumulator arrangement 42 includes a least one plate, shown asfirst plate 44, oriented on the clean air side 15 of the tubesheet 28and adjacent to the opening 30 of the tubesheet 28. The first plate 44may be any type of wall, sheet metal, panel, baffle, rigid plastic, orgenerally non-porous solid structure that is oriented to the adjacentrespective opening in the tubesheet 28 for the respective filter element32.

In certain implementations, the accumulator arrangement includes asecond plate 46 oriented at an opposite end of the opening 30 at thetubesheet 28 from the first plate 44. In the embodiment shown, the firstand second plates 44, 46 are aligned with the general direction of thepulse, but the angle does not necessarily need to be the same as theangle of the pulse direction. FIG. 2 illustrates a center line of thedirection of the pulse at 48. The first plate is mounted at a firstangle 50 relative to the tubesheet 28. The first angle is within about85° of center line 48 of a direction of the pulse. Similarly, the secondplate 46 is mounted at a second angle 52 relative to the tubesheet 28.The second angle 52 is within about 85° of the center line 48 of adirection of the pulse. In some embodiments, the first angle 50 and thesecond angle 52 are equal. In other embodiments, the first angle 50, andsecond angle 52 are unequal. In some embodiments, the first angle 50 andthe second angle 52 are within 85° of being parallel to each other. Theangles 50, 52 of the plates 44, 46 are selected based upon the angle 53of the pulse. If the angles are too small (such as under about 15° frombeing parallel to the centerline 48) then the problem is pressure lossassociated with primary flow.

In certain implementations, the accumulator arrangement includes a thirdand a fourth plate 100 oriented at the sides of the opening 30 at thetubesheet 28 between the first plate 44 and second plate 46. The thirdand fourth plates 100 are aligned generally normal to the tubesheet 28,but the angle does not necessarily need to be 90°. The height L₃ ofplate 100, shown at 101, can range from 0.00 inch to equal to the lengthL₂ of plate 46. The height of plate 100 at location 102 can range from0.125×L₁ to 1.50×L₁, preferably 1.00×L₁.

In certain applications, the accumulator arrangement includes a fifthplate 103. The length L₄ of this plate can range from 0.25×L₅ to 1.0×L₅,preferably 0.25×L₅. The location of plate 103 at position 102 can rangefrom 0.25×L₁ to 1.0×L₁, preferably 1.0×L₁. The angle of plate 103 inrelation to the tubesheet 28 can range from +45° to −45°, preferablyparallel or 0°.

In certain applications, plates 44, 46, 100, 103 will be curved. Thecurved portion can be located at one or both ends or may encompass theentire length L₁, L₂, L₃, L₄, of the plates 44, 46, 100, 103.

As illustrated in FIG. 2, the first plate 44 has length L₁ which ispreferably no longer than 3 times the length of the respective opening30 in the tubesheet 28. This is because primary flow pressure lossincreases with increase in length. Preferably, the length L₁ has alength that is between 25-75% of a length of the respective opening 30in the tubesheet 28. In preferred arrangements, the blow pipe 40 isspaced no more than 30-40 times of an inside diameter of the blowpipefrom the tubesheet to eject the pulse.

In FIG. 2, reference numeral 72 shows the offset between the pulsecenter line 48 and a center of the filter element 32. This shows how thecenter line 48 of the pulse is not always in alignment with the centerof the filter element 32.

In one embodiment, the plate that is closer to the respective blow pipe40 (in the embodiment illustrated, the second plate 46) has a lengththat is shorter than the other plate (in this example, the first plate44). In one embodiment, this shorter plate 46 has a length that is notless than 5% of a length of the respective opening 30 in the tubesheet28. This arrangement is advantageous because of both material savingsand pressure loss associated with pumping air flow.

Attention is directed to FIG. 3. In FIG. 3, the arrow 62 represents theprior art pulse direction. In the prior art, the standard pulsedirection is directed perpendicular or normal to the plane 60 thatcontains the tubesheet 28. Angle 64 shows the angle that is offset tothe vertical direction, or the direction from the standard, prior artdirection shown by arrow 62. A typical pulse expansion is shown at angle66, from the blow pipe 40. As explained above, the exhaust jet from theblow pipe 40 creates a diameter D2, covering a larger surface area inthe opening 30 of tubesheet 28, versus diameter D1 that comes from theexhaust jet shown at arrow 62 in the prior art arrangement. In FIG. 4,an alternative arrangement of the filter element 32 relative to thetubesheet 28 is shown. In the FIG. 4 embodiment, the filter element 32is offset at an angle 70 relative to the tubesheet opening 30. Thisarrangement results in an angle 68 of the pulse direction 48 greater atthe face of the filter 36 than the angle 68 of the pulse direction 48 atthe plane 60 of the tubesheet opening 30.

One useful arrangement has the following angles and dimensions: Angle 68is 55°-65°, preferably 61°; angles 50 and 52 are equal and 65°-72°,preferably 67°-68°; first and second plates 44, 46 are parallel; offset72 is about 3 inches; length L₁ is about 8-16 inches, preferably about12 inches; and length L₂ is about 6-10 inches, preferably about 8.0inches. The blowpipe is spaced no more than 30-40 times of an insidediameter of the blowpipe from the tubesheet to eject the pulse.

FIG. 5 illustrates principles of this disclosure by pulse-cleaning aV-pack filter arrangement 120. The V-pack filter arrangement 120includes first and second filter elements 32 arranged together in theform of a V. Air to be cleaned flows through the filter elements 32 intothe interior of the V. When the filter elements 32 are to be cleaned,pulses are ejected from blowpipes 40. In the embodiment shown, there isone blow pipe 40 oriented at a first of the filter elements 32, andanother blowpipe 40 oriented at a second of the filter elements 32.Again, in accordance with principles of this disclosure, the pulse thatcomes from each blowpipe 40 is at an angle that is not normal to a planeof the opening 30 and is not in line with a general direction offiltration flow through each filter element 32. Each pulse hits about adistance L₃, which is spaced from a point half of the overall distanceL₁ of each filter element 32. Each of the blowpipes 40 is spaced adistance 122 from an end point of the filter elements 32 which is about10-40 times the diameter of each blowpipe 40. While a V-pack filterarrangement 120 is shown, the arrangement of FIG. 5 can also represent aconical-shaped filter element, in which the side wall of the filterelement is shaped in the form of a cone truncated cone.

In FIG. 6, a cylindrical filter arrangement 130 isschematically-illustrated as being pulsed in accordance with principlesof this disclosure. The filter element 32 is embodied as a cylindricalelement having a circular cross-section. The element 32 is pulse cleanedas described above. In particular, it can be seen how the blowpipe 40 isoriented relative to the filter element 32 such that a pulse that comesfrom the blowpipe 40 is at an angle that is not normal to a plane of theopening 30 and is not in line with a general direction of filtrationflow through the filter element 32. The blowpipe 40 is illustrated asbeing at an angle of 5°-45° relative to the cylindrical wall 32 of thefilter arrangement 130. The pulse impacts the filter element 32 atapproximately the point L₂, which is spaced from a point that is half ofthe overall distance L₁ of the length of the filter element 32. Thecylindrical element 32 can also be pulsed with a plurality of blowpipes40. The blowpipe 40 is spaced a distance 122 from the end of the filterelement 32 which is about 10-40 times the diameter of the blowpipe 40.

FIGS. 7A and 7B each illustrate multiple filters stacked axiallyrelative to each other. In FIG. 7A, there are two cylindrical filterelements 32 arranged axially end-to-end. In FIG. 7B, a conical elementis shown stacked or aligned axially next to a cylindrical element. Ineach case, the filter elements 32 are pulse cleaned, in that theblowpipe 40 is oriented relative to the filter element 32 in a planethat contains the respective opening 30 in tubesheet 28 for therespective filter elements 32, such that a pulse that comes from theblowpipe 40 is at an angle that is not normal to a plane of the opening30 and is not in line with a general direction of filtration flow of thefilter element 32. As described above, distance 122 is about 10-40 timesthe diameter of the blowpipe 40 between the tubesheet 28 and theblowpipe 40.

FIG. 8 shows a schematic diagram of a modified system 10′, whichillustrates a dust filter using a method of pulse cleaning filter mediaby directing a fluid pulse at the filter media that exhausts from morethan one blowpipe 40. In the embodiment shown, cylindrical filterelements 32 are shown in a stacked configuration, such as the embodimentof FIG. 7A. As described above, the filter media can be embodied inother forms such as a panel, a conical element, a V-pack element, orcombinations. In the embodiment shown, there are two blowpipes 40directed at each filter element arrangement 32. The blowpipes 40 areoriented as described above, such that the fluid pulses are at an anglethat is not normal to a plane of the opening of the tubesheet 28 andalso not in line with a general direction of filtration flow through thefilter media 32.

1. A method of pulse cleaning filter media in a panel, cylindrical,conical, or V-pack style filter oriented in an opening of a tubesheet;the method comprising: (a) directing a fluid pulse at the filter mediaat an angle that is: (i) not normal to a plane of the opening of thetubesheet; and (ii) not in line with a general direction of filtrationflow through the filter media.
 2. A method according to claim 1 wherein:(a) the step of directing a fluid pulse includes directing the fluidpulse at an angle of 5-85° inclusive.
 3. A method according to claim 1wherein: (a) the step of directing a fluid pulse includes using ablowpipe spaced no more than 10-40 times of an inside diameter of theblowpipe from the tubesheet to eject the pulse.
 4. A method according toclaim 1 wherein: (a) the step of directing a fluid pulse includestrapping at least a portion of the fluid pulse by using an accumulator.5. A method according to claim 4 wherein: (a) the step of trapping atleast a portion of the fluid pulse includes using at least one plateoriented on a clean air side of the tubesheet and adjacent to theopening in the tubesheet.
 6. A method according to claim 5 wherein: (a)the step of using at least one plate includes using two plates orientedon the clean air side of the tubesheet and adjacent to opposite ends ofthe opening in the tubesheet.
 7. A method according to claim 1 wherein:(a) the step of directing includes directing a fluid pulse at thepanel-style filter having media including one of: pleated, Z-media,depth; HEPA; or mini V-packs.
 8. An air cleaner comprising: (a) ahousing including a dirty air inlet, a clean air outlet, and aninterior; (b) a tubesheet in the housing interior having a plurality ofopenings; (c) a plurality of filters, each filter being mounted in arespective one of the openings in the tubesheet; and (d) a plurality ofblowpipes; each blowpipe being oriented to direct a fluid pulse at arespective one of the filters at an angle that is: (i) not normal to aplane of the openings in the tubesheet; and (ii) not in line with ageneral direction of filtration flow through the respective filters. 9.An air cleaner according to claim 8 further comprising: (a) anaccumulator arrangement oriented adjacent to the openings in thetubesheet on a downstream side of the tubesheet.
 10. An air cleaneraccording to claim 9 wherein: (a) the accumulator arrangement includes aplurality of plates oriented adjacent to the openings in the tubesheet.11. An air cleaner according to claim 9 wherein: (a) the accumulatorarrangement includes, for each opening in the tubesheet, a first andsecond plate adjacent to opposite ends of the tubesheet opening.
 12. Anair cleaner according to claim 11 wherein: (a) the first plate ismounted at a first angle relative to the tubesheet, the first anglebeing within about 85° of a center line of a direction of the pulse; and(b) the second plate is mounted at a second angle relative to thetubesheet, the second angle being within about 85° of a center line of adirection of the pulse.
 13. An air cleaner according to claim 12wherein: (a) the first angle and second angle are equal.
 14. An aircleaner according to claim 12 wherein: (a) the first angle and secondangle are unequal.
 15. An air cleaner according to claim 12 wherein: (a)the first angle and second angle are within 85° of being parallel toeach other.
 16. An air cleaner according to claim 11 wherein: (a) atotal length of the first plate and second plate added together is nolonger than twice of a length of the respective opening in thetubesheet.
 17. An air cleaner according to claim 11 wherein: (a) alength of the first plate about 300% of a length of the respectiveopening in the tubesheet.
 18. An air cleaner according to claim 11wherein: (a) the first plate and second plate are equal in length. 19.An air cleaner according to claim 11 wherein: (a) the first plate andsecond plate are of unequal length.
 20. A method of pulse cleaningfilter media in a panel, cylindrical, conical or V-pack style filterwith more than one blow pipe, the method comprising: (a) directing afluid pulse at the filter media that exhausts from more than one blowpipe.